Often, columns of power thyristors and of power diodes are installed between two end plates, the assembly thus formed being fixed in a sealed chamber which contains a fluorinated hydrocarbon. These power semiconductors are used for example to control traction motors in the field of railway technology. The pulse transformers and resistor-capacitor circuits serve respectively to fire and to protect the power semiconductors. In general, the pulse transformers and protection circuits are disposed behind one of the plates at the bases of the columns and in the axes of the columns of semiconductors. It follows that the connections between the pulse transformers and the triggers of the thyristors are excessively long and result in electrical interference. Indeed, the connections for some of the thyristors disposed on the side furthest from the transformers have to run right along the column of semi-conductors.
Preferred embodiments of the support device in accordance with the present invention remedy this drawback. The transformers are disposed in such a way that the connections are shorter than in devices of the prior art.